Thread: I pitched my first prop today
09-19-2005, 07:29 PM #1
I pitched my first prop today
I used this impeller pitch gauge from Watcon.
I just ordered a new prop from Richard and wanted to transpose my pitch from my old cavitation burned prop to the new prop. I read my old prop with the pitch gauge and was shocked to see how far off one of the blades was. I used the 3 good blades as a baseline to use for the new prop. What is even more shocking was how far off the new prop was. It was supposed to be a 14/19R which is supposidly pitch blocked and checked for accuracy, but two blades were out of whack. Maybe it wasn't a 14/19R though as it doesn't say that on the prop, or the box.
Anyway, i got the new prop bent to the specs of my old prop and ended up fixing the one out of whack blade on my old prop. It was with this out of whack, cavitation burned prop that I ran 77.2 with yesterday. I wonder how much speed it cost me with with that one out of whack blade? Can't wait to see what this new prop does for me.
09-19-2005, 07:34 PM #2
09-19-2005, 08:34 PM #3
- Join Date
- May 2005
What was the pitch on you old impeller? Are you pitching the new one to the same spec as the old one? What were your rpm's after 2 minutes of riding vs. 30 minutes of riding in 90+ weather after heat soak? Mine would drop 100 rpm in 90+ air and 90 water. At 80 air and water I notice no heat fade.
In the cooler temps, 80 degree air and water, I have to back off the throttle slightly and am hitting the rev limiter. Tried the 81 mm ring and was still on the limiter but noticed reduced accelleration, so went back to the 82 mm. Am having Dave @ Impros bend me a 14/19.5 to use in temps below 80 and will use my current 14/18.5 for the hot weather. From what I've experienced so far, I'm not sure you can use one impeller on a stage 3 RXP for all weather conditions. I believe Glenn @ Skat Trak said he would make me an 83 mm ring. That might work with the 14/19.5 in the summer.
These skis are difficult to dial in are'nt they?
09-19-2005, 08:45 PM #4
Yes, they are very difficult to dial in
I have no idea what pitch my old prop was as PPG did it. I just made sure the lines matched up from my old prop to my new prop. Wasn't too hard, just took some time.
Heat fade? I have none My RPM's maintain all day long. I attribute this to my cold air intake and the 158 degree thermostat.
09-19-2005, 08:50 PM #5Originally Posted by Green Hulk
I have to turn on my rear atwood fan during hot weather or I'll loose about 100 rpm. When it is 95+ and I don't have it on I loose almost a mph.
You can see pictures at the thread that says 2005 RXT stage 1 season 1.
Try taking your back and front seat off and ride. If that helps then you need some venting.
09-19-2005, 08:51 PM #6
Any heat needed to bend it?
What did you use to Bend it?
Doesn't the ring tell you the pitch? So you would know old pitch for the new one?
Cool deal. Man your really gonna have fun now.
09-19-2005, 08:58 PM #7
No heat needed. I used a crecent wrench as per instruction from the prop bending guru's
The ring tells you the pitch, but im not quite sure how to read it just yet... LOL!
09-19-2005, 09:07 PM #8
I noticed that the box Jerry's 14/19 came in didn't have "R" after the number. Seems that some of the Riva props do and some don't. None of the SRX-CD props have the "R" stamped anywhere on them, just the pitch. The prop had been balanced as there was a balancing hole drilled in the rim. I'm about as curious as Jerry to see what the trued props do performance wise. I hope the 'variable' pitch doesn't mean that each blade is different.
09-19-2005, 09:10 PM #9
It's all good Rich. I think i have it bent up just right and will hopefully go out for testing in the next day or so.
09-19-2005, 10:16 PM #10
Wow think of the possibilities that opens up. Tweaking things on your own like that could probably gain more accurate results due to the quicker turn around time by doing it yourself.
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